Preheat oven to 350 degrees Fahrenheit.
In a large bowl, pour out the devils food cake mix and add in the eggs, vegetable oil, greek yogurt (or sour cream), warm water and instant chocolate pudding mix.
18.25 ounces devil's food chocolate cake mix, 4 large eggs, 1 cup vegetable oil, 1 cup Greek yogurt or sour cream, 3/4 cup warm water, 5.7 ounces instant chocolate pudding mix
Scoop half of the devils food cake batter into a 13x9 oven safe baking dish. Arrange the graham crackers in a layer on top of the batter. Pull the jumbo marshmallows apart into halves and place them on top of the graham crackers. Sprinkle on half of the chocolate chips or chocolate chunks.
8 graham cracker sheets, 2 cups jumbo marshmallows, 1.5 cups semi-sweet chocolate chips or chunks, divided
Scoop the second half of the devils food cake batter on top. Spread it evenly over the s’mores ingredient using a rubber spatula. Sprinkle the remaining chocolate chips or chocolate chunks on top.
Bake for about 45-50 minutes. The best way to check for doneness is by poking a toothpick or skewer into the cake. If it pulls out clean, the cake is cooked. If some of the cake crumbles stick to it, then the cake needs a little bit more time!
Serve warm!